The invention relates to a process for converting maleic anhydride into .gamma.-butyrolactone by treating the anhydride with hydrogen in the presence of co-catalysts comprising palladium and nickel-copper chromite at elevated pressure and temperature.
It is known to convert maleic anhydride consecutively into succinic acid, .gamma.-butyrolactone and tetrahydrofuran by hydrotreatment. The difficulty is to obtain the particular desired product with maximum purity. While many catalysts have been proposed for the manufacture of .gamma.-butyrolactone by hydrotreatment of maleic anhydride, the selectivity of the catalysts employed and the yields of .gamma.-butyrolactone obtained leave room for improvement. Illustratively, U.S. Pat. No. 3,113,138 discloses a process wherein .gamma.-butyrolactone is obtained by hydrotreating an anhydride using palladium on activated carbon as the catalyst. The principal disadvantage in this process is that it requires the use of a solvent from which the final or end product must be recovered.
It is the object of this invention to provide a process for converting maleic anhydride to .gamma.-butyrolactone in high yields.
Another object of this invention is to provide a process for converting maleic anhydride to .gamma.-butyrolactone in the presence of selective co-catalysts.
Yet another object of this invention is to provide a process wherein the removal of the solvent is no longer necessary and where high yields in .gamma.-butyrolactone are obtained.
Other objects and advantages will become apparent from a reading of the following detailed description and examples.